PONTIAC, Mich. — A 75-year-old Detroit-area woman was convicted of second-degree murder on Tuesday for shooting her teenage grandson six times during an argument last spring.

Sandra Layne's trial was not about whether she pulled the trigger last spring at her home in West Bloomfield Township. It boiled down to whether she would be convicted of first-degree murder or a lesser charge, or cleared based on self-defense.

Layne struck Jonathan Hoffman with six of 10 shots fired over a six-minute span. The jury heard a recording of the 17-year-old's desperate call to 911 and even more shots while he was on the line.

The jury delivered the verdict on the first full day of deliberation. It also convicted Layne of using a firearm during a felony.

Prosecutor Paul Walton told jurors that Layne never rushed out of the West Bloomfield Township home, despite claiming to be afraid of her grandson, and never called for an ambulance to help him. She claimed that she shot him after Hoffman struck her during a heated argument about money and a plan to flee Michigan because of a failed drug test.

"I wanted him to pay attention to me. He had to listen. It wasn't a conversation. It was arguing. Swearing," Layne said in tearful testimony last week, explaining why she pulled out a gun.

But Walton pointed out that Layne never complained to police about being attacked. A hospital nurse who examined her after her arrest said Layne had no injuries and spoke lovingly about Hoffman.

Defense attorney Jerome Sabbota asked jurors to view the incident through the eyes of a woman in her 70s. He said Layne was taking care of a teen who had used drugs and brought strangers to the home. Hoffman's parents were in Arizona during his senior year of high school.

"Her adrenalin is pumping. You're not calm," Sabbota said in his closing remarks. "Boom, boom, boom — you pull the trigger."